Offset printing presses employ blanket cylinders for transferring images from printing plates to a web material. Typically, blanket cylinders have printing blankets with rubber surfaces mounted thereon which transfer the images.
Continuous printing is made possible by wrapping a printing plate or a plurality of printing plates around the surface of a plate cylinder designed for rotation in contact with the blanket cylinder. In operating blanket-to-blanket presses, a web of material passes between two blanket cylinders mounted such that one blanket cylinder serves as an impression cylinder for the other, resulting in simultaneous printing on both sides of the web of material.
However, during continuous offset printing, the printing blankets mounted on the blanket cylinders accumulate foreign matter such as dried ink or ink build-up, lint, dust, clay, dirt and the like which must be removed to maintain the quality of the printed product. Therefore, during a specific run or job, the printing blankets must be cleaned at various times during the running of the job. Additionally, the printing blankets must also be cleaned to remove the image when the job is complete. Still further, the blankets must be cleaned during "make ready" operations. Each time the printing blankets must be cleaned, there is machine down-time.
In the past, printing blankets were cleaned by hand. However, this method had numerous problems and was extremely time consuming. Recently, several automatic and semi-automatic blanket cleaning devices have been developed and employed for accomplishing this cleaning. However, these devices have a number of drawbacks.
For one, these devices are not capable of removing blanket wash waste without dirtying the devices themselves in the process, i.e., they are not self-cleaning. Second, these devices create a mist of blanket wash waste which invades and contaminates surrounding inker and dampening units disrupting the quality of the printed product.